U.S. Pat. No. 3,766,851 issued Oct. 23, 1973 to E. Sirvet et al. for Continuous Can Printer and Handling Apparatus describes relatively high speed apparatus for applying decorations to the exterior of cylindrical containers while they are mounted on mandrels disposed along the periphery of a large rotating wheel like carrier. In continuous can printer apparatus of this type, means are provided to assure that when a mandrel moves through the decorating zone along a normal path for printing, such mandrel is properly loaded with a cylindrical container. If a particular mandrel is empty or is not properly loaded, means are provided to assure that this mandrel and/or an improperly loaded container do not engage the printing blanket. An example of prior art means for retracting unloaded and misloaded mandrels to a no-print position is disclosed in U.S. Pat. No. 4,140,053 issued Feb. 20, 1979 to J. P. Skrypek et al. for Mandrel Mounting and Trip Mechanism For Continuous Motion Decorator.
In the aforesaid U.S. Pat. No. 4,140,053 each mandrel is part of a subassembly that is mounted on a pivot axis to a continuously rotating carrier. When an unloaded or misloaded mandrel is detected a linear actuator acting through a crank and an eccentric moves the pivot axis for the entire subassembly and in so doing moves the unloaded or misloaded mandrel away from its normal path so that neither the mandrel nor a misloaded container will engage the printing blanket. While this type of mechanism operates well at high production rates, say 1200 cans per minute, mounting and dismounting of the subassembly from the carrier is time consuming and adjustments must be made while the subassembly is mounted on the carrier.